public class Demo19 {
    private volatile static int count = 0;

    public static void main(String[] args) throws InterruptedException {
        // 先创建出一个对象, 使用这个对象作为锁
        Object locker = new Object();
        Object locker2 = new Object();

        Thread t1 = new Thread(() -> {
            for (int i = 0; i < 50000; i++) {
                // synchronized (locker) {
                    count++;
                // }
            }
        });
        Thread t2 = new Thread(() -> {
            for (int i = 0; i < 50000; i++) {
                // synchronized (locker) {
                    count++;
                // }
            }
        });
        t1.start();
        t2.start();
        t1.join();
        t2.join();
        System.out.println("count = " + count);
    }
}